docs: def _post_init(self):
          """
          The standard rootpy _post_init method that is used to initialize both
          new Trees and Trees retrieved from a File.
          """
          if not hasattr(self, '_buffer'):
              # only set _buffer if model was not specified in the __init__
              self._buffer = TreeBuffer()
          self.read_branches_on_demand = False
          self._branch_cache = {}
          self._current_entry = 0
          self._always_read = []
          self.userdata = UserData()
          self._inited = True